Electrically-insulating tape



H. I. DIAMOND.

ELECTRICALLY INSULATING TAPE. APPLICATION FILED JAN. 6. 1920.

1,368,025. Patented Feb. 8,1921.

Friction material UNITED STATES PATENT OFFICE.

HARRY I. DIAMOND, or ATLANTA, GEORGIA.

ELECTRICALLY-INSULATING TAPE.

Specification of Letters Patent.

Patented Feb. 8, 1921.

Application filed January 6, 1920. Serial No. 349,771.

and eliminate certain kinds of imperfect work now common whereunfaithful workmen are employed.

It is usual to wind about bare conductors strips of good insulatingmaterial such as plastic, adhesive rubber or gutta percha compound andafterward to cover this insulation by winding about it a strip of fabrichaving friction material upon its face. It sometimes happens that aworkman exhausts his supply of insulating strips while having left astock of covering strip, which is itself capable of insulating in somedegree. If, for example, he must thusomit the insulating strip on asplice or two or else return on another day to complete the workproperly, he may save time by using the covering strip alone. The badwork cannot be discovered by ordinary inspection, yet later it may leadto very serious loss.

In the accompanying drawings,

Figure 1 is a view showing a portion of my novel tape with its severallayers broken away to show in succession a small portion of the variouslayers.

Fig. 2 is a cross section of the same tape showing the layers greatlyexaggerated in thickness.

In these figures, A represents a strip of approved insulating material,preferably pliable adhesiie rubber or gutta percha compound, and B anequal superposed adherent strip, preferably of Holland or fabric filledand sized, the functionof this strip being the temporary protection ofthe strip when rolled and the prevention of too strong so adhesion ofthe adjacent friction surface.

mprovements in Electrically-Insu- When a piece of the strip is to beused, this layer is stripped from it. C represents a fabric layer havingon each face a coating D of soft highly adhesive friction material. Whenthe tape made up of these several connected layers is coiled uponitself, the outer friction layer adheres with moderate tenacity to thelayer B but not so strongly as to prevent unwinding of the tape by astrong pull upon its end portion. In using the tape a portion from whichthe layer B has been stripped is wound firmly around the conductor to beinsulated, usually forming a helix with its margins overlapping, andpressed down so that all air and moisture are excluded and all crevicesand interstices are closed. This operation is quickly and perfectlyperformed and with almost unavoidable perfection owing to the characterof the tape and the fact that it is soft and lies between theoverlapping surfaces of the insulation proper. The entire tape is putsecurely in place in far less time than is usually required to apply thelayer A, and the work is less likely to be imperfect at any point, theconductor lying in the axis strip of fabric having both faces coatedwith soft, insulating, highly adhesive friction material, said plasticmaterial having its otherwise exposed face protected by a slightlyadhering strip itself of non-adherent material.

2. Insulating tape consisting of a strip of plastic adhesive material ofhighly insulating character superposed on an analogous strip of fabrichaving both its faces coated with friction material.

,3. Insulating tape consisting of a strip of fabric impregnated withinsulating material, such as rubber or gutta percha compound, or otherapproved insulating material, bearing upon each face a coat of frictionmaterial, and a superposed strip of plastic, adhesive, rubber-like"insulating compound secured permanently upon one ofthe frictioned facesof the fabric strip.

In testimony whereof I hereunto aflix my signature.

HARRY I. DIAMOND;

